1. Field of the Invention
The present invention relates to a workpiece conveyor and a machine tool.
2. Description of the Related Art
A lathe that is a machine tool may include a workpiece conveyor for conveying a workpiece between a spindle that holds the workpiece to be processed and a workpiece loading/unloader. Such a known workpiece conveyor includes a chuck that holds the workpiece and a movable body that holds the chuck and moves (refer to Japanese Unexamined Patent Publication No. 2004-216504, for example). In the workpiece conveyor in Japanese Unexamined Patent Publication No. 2004-216504, the movable body and the chuck move along one linear guide.
When one guide supports the movable body, the movable body overhangs the guide and thus, the movable body is required to have enough stiffness to prevent deformation. For this reason, the movable body becomes heavy, obstructing high-speed movement. Thus, Japanese Unexamined Patent Publication No. 2004-216504 proposes that the movable body is guided by two guides spaced apart from each other in parallel, rather than with one guide. With this structure, the movable body extends across the two guides. However, with the structure using two guides, each guide and the movable body may receive a load generated by the movement of the movable body due to amounting error between the guides in height or distance, disadvantageously limiting smooth movement of the movable body and shortening the life of the guides. Although the two guides can be positioned with respect to a frame with high accuracy, bending of the frame and the like need to be considered, which requires a large workload during installation of the guides.